From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp.codeaurora.org by pdx-caf-mail.web.codeaurora.org (Dovecot) with LMTP id IrJDDa9RGVsWEQAAmS7hNA ; Thu, 07 Jun 2018 15:40:44 +0000 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id ECE60608B8; Thu, 7 Jun 2018 15:40:43 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on pdx-caf-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI autolearn=unavailable autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by smtp.codeaurora.org (Postfix) with ESMTP id 5E4A760590; Thu, 7 Jun 2018 15:40:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 5E4A760590 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934637AbeFGOlm (ORCPT + 25 others); Thu, 7 Jun 2018 10:41:42 -0400 Received: from mga09.intel.com ([134.134.136.24]:36346 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932931AbeFGOle (ORCPT ); Thu, 7 Jun 2018 10:41:34 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 07 Jun 2018 07:41:31 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.49,486,1520924400"; d="scan'208";a="62632631" Received: from 2b52.sc.intel.com ([143.183.136.51]) by orsmga001.jf.intel.com with ESMTP; 07 Jun 2018 07:41:30 -0700 From: Yu-cheng Yu To: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , "H.J. Lu" , Vedvyas Shanbhogue , "Ravi V. Shankar" , Dave Hansen , Andy Lutomirski , Jonathan Corbet , Oleg Nesterov , Arnd Bergmann , Mike Kravetz Cc: Yu-cheng Yu Subject: [PATCH 04/10] x86/cet: Handle thread shadow stack Date: Thu, 7 Jun 2018 07:38:01 -0700 Message-Id: <20180607143807.3611-5-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20180607143807.3611-1-yu-cheng.yu@intel.com> References: <20180607143807.3611-1-yu-cheng.yu@intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When fork() specifies CLONE_VM but not CLONE_VFORK, the child needs a separate program stack and a separate shadow stack. This patch handles allocation and freeing of the thread shadow stack. Signed-off-by: Yu-cheng Yu --- arch/x86/include/asm/cet.h | 2 ++ arch/x86/include/asm/mmu_context.h | 3 +++ arch/x86/kernel/cet.c | 34 ++++++++++++++++++++++++++++++++++ arch/x86/kernel/process.c | 1 + arch/x86/kernel/process_64.c | 7 +++++++ 5 files changed, 47 insertions(+) diff --git a/arch/x86/include/asm/cet.h b/arch/x86/include/asm/cet.h index 5507469cb803..c8fd87e13859 100644 --- a/arch/x86/include/asm/cet.h +++ b/arch/x86/include/asm/cet.h @@ -19,6 +19,7 @@ struct cet_stat { unsigned long cet_get_shstk_ptr(void); int cet_push_shstk(int ia32, unsigned long ssp, unsigned long val); int cet_setup_shstk(void); +int cet_setup_thread_shstk(struct task_struct *p); void cet_disable_shstk(void); void cet_disable_free_shstk(struct task_struct *p); int cet_restore_signal(unsigned long ssp); @@ -28,6 +29,7 @@ static inline unsigned long cet_get_shstk_ptr(void) { return 0; } static inline int cet_push_shstk(int ia32, unsigned long ssp, unsigned long val) { return 0; } static inline int cet_setup_shstk(void) { return 0; } +static inline int cet_setup_thread_shstk(struct task_struct *p) { return 0; } static inline void cet_disable_shstk(void) {} static inline void cet_disable_free_shstk(struct task_struct *p) {} static inline int cet_restore_signal(unsigned long ssp) { return 0; } diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h index cf9911b5a53c..42395257efc3 100644 --- a/arch/x86/include/asm/mmu_context.h +++ b/arch/x86/include/asm/mmu_context.h @@ -13,6 +13,7 @@ #include #include #include +#include extern atomic64_t last_mm_ctx_id; @@ -228,6 +229,8 @@ do { \ #else #define deactivate_mm(tsk, mm) \ do { \ + if (!tsk->vfork_done) \ + cet_disable_free_shstk(tsk); \ load_gs_index(0); \ loadsegment(fs, 0); \ } while (0) diff --git a/arch/x86/kernel/cet.c b/arch/x86/kernel/cet.c index 6f445ce94c83..156f5d88ffd5 100644 --- a/arch/x86/kernel/cet.c +++ b/arch/x86/kernel/cet.c @@ -103,6 +103,40 @@ int cet_setup_shstk(void) return 0; } +int cet_setup_thread_shstk(struct task_struct *tsk) +{ + unsigned long addr, size; + struct cet_user_state *state; + + if (!current->thread.cet.shstk_enabled) + return 0; + + state = get_xsave_addr(&tsk->thread.fpu.state.xsave, + XFEATURE_MASK_SHSTK_USER); + + if (!state) + return -EINVAL; + + size = tsk->thread.cet.shstk_size; + if (size == 0) + size = SHSTK_SIZE; + + addr = shstk_mmap(0, size); + + if (addr >= TASK_SIZE) { + tsk->thread.cet.shstk_base = 0; + tsk->thread.cet.shstk_size = 0; + tsk->thread.cet.shstk_enabled = 0; + return -ENOMEM; + } + + state->user_ssp = (u64)(addr + size - sizeof(u64)); + tsk->thread.cet.shstk_base = addr; + tsk->thread.cet.shstk_size = size; + tsk->thread.cet.shstk_enabled = 1; + return 0; +} + void cet_disable_shstk(void) { u64 r; diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index b3b0b482983a..ae56caee41f9 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -127,6 +127,7 @@ void exit_thread(struct task_struct *tsk) free_vm86(t); + cet_disable_free_shstk(tsk); fpu__drop(fpu); } diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 12bb445fb98d..6e493b0bcedd 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -317,6 +317,13 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long sp, if (sp) childregs->sp = sp; + /* Allocate a new shadow stack for pthread */ + if ((clone_flags & (CLONE_VFORK | CLONE_VM)) == CLONE_VM) { + err = cet_setup_thread_shstk(p); + if (err) + goto out; + } + err = -ENOMEM; if (unlikely(test_tsk_thread_flag(me, TIF_IO_BITMAP))) { p->thread.io_bitmap_ptr = kmemdup(me->thread.io_bitmap_ptr, -- 2.15.1